ABSTRACT This is a renewal (competing continuation) for a study that focuses on preventing drug use and related risky behavior in club settings that feature electronic music dance events (EMDEs). Our first study provided evidence that the number of drug users attending this type of event was sufficiently large to warrant the next step, i.e., to test the feasibility of implementing previously-proven environmental prevention strategies in clubs. The proposed study will implement and test the feasibility of implementing environmental prevention strategies designed to reduce drug use and other risky behaviors in clubs (e.g., presence of drug use and drug users in the clubs and drug-related and other risky behaviors such as drugged driving, overdoses, sexual risk-taking, aggressive behaviors). Our specific aims are as follows: Specific Aim 1: To measure environmental indicators, host policies, and patron characteristics and behaviors prior to implementing environmental change strategies in clubs. Specific Aim 2: To implement environmental interventions in the clubs and to assess and track the feasibility of implementing these strategies and fidelity of this implementation. Specific Aim 3: To examine the changes from pre- to post-intervention levels of drug use and drug related risks, accounting for the changes in the adoption of environmental prevention strategies. A total of four clubs will be included in this feasibility study to test the environmental prevention strategies. Two clubs will be randomly assigned to receive the intervention at the start of the second year, while the other two clubs will be required to wait an additional year for the intervention. This modified crossover design is discussed in our analyses section. Our data collection timeframe includes 5 major waves of data collection approximately six months apart and beginning with baseline measures prior to intervention. Each major data wave will include multiple sources of data: Observations of clubs, Host/staff interviews (20 interviews per wave) and Portal data collections from patrons (n=2000). Advertising assessments also will be collected monthly. Additional observations of clubs will occur halfway between the major data wave collection and advertising assessments will occur monthly. Measures from our prior studies as well as some additional questions are planned (e.g., host and staff interviews about barriers encountered in the implementation of environmental strategies). Hence, the overall design for this competitive renewal builds upon the measures we have tested in the prior studies (see appendices) as well as implementing new measures based upon the intervention and what we have learned from the prior work (see measurement section below). The proposed application is not an efficacy study, rather a feasibility study designed to test whether the environmental strategies for clubs can be implemented, to assess the barriers and impediments to the implementation and to demonstrate change within a small number of clubs that can warrant a full-scale efficacy study across numerous sites in a subsequent application.